FIGURE 7.

Paraffin sections of the lungs of vaccinated and unvaccinated hamsters. Pathohistological picture of the lung of unvaccinated hamsters (a–d, 1st row) and vaccinated hamsters challenged after 42 days (e–h, 2nd row), and vaccinated hamsters challenged after 6 months (i–l, 3rd row) on days 3, 5, 7, and 14, respectively after challenge with the wild homologous SARS-CoV-2 virus; 42 indicates vaccinated group challenged 42 days after vaccination; 6 indicates vaccinated group challenged 6 months after vaccination. The 4th row shows the histological picture of the lung of control hamsters on days 3, 5, 7, and 14 (m–p), indicative of normal lung microstructure. Alveoli, bronchioles, capillaries, and the respiratory membrane are clearly observed. The images were stained with hematoxylin and eosin. Image magnification: × 400. DPI, days post infection.